Mexican soap star Eduardo Yanez is under criminal investigation for viciously slapping a reporter during a red carpet event ... TMZ has learned. Law enforcement sources tell us, Univision reporter Paco Fuentes filed a police report with the LAPD, claiming assault and battery. The slap was captured on video . Yanez lost it after Fuentes tried shaming him by saying his son had to set up a GoFundMe account to pay for car repairs because Yanez wouldn't. Yanez and his son have a strained relationship that became very public back in June after Yanez's son accused him on Twitter of being a drug addict, racist and woman abuser. We're told the investigation is not complete. If charges are filed ag... Full story